Analog self-interference cancellation based on zero-forcing sampling for in band full duplex radios

•A Self-Interference(SI) cancellation method for full-duplex radios is proposed.•An auxiliary signal is designed by channel estimation and zero-forcing function(ZFF).•A closed-form expression of the ZFF is derived according to the Z transformation.•An orthogonal pilot structure is designed to improve the channel estimation accuracy.•SI is removed while ADC samples the received signal by utilizing the proposed method.